The effects of environmental factors on plant diversity of Darab natural ecosystems in Fars province, Iran.

This research quantitatively evaluated the diversity of plants to protect vulnerable species. To measure vegetation information, the appropriate sampling plot size was determined based on the canopy cover of the dominant species of the study area (1 m2). Then, in each unit, sampling was done along 3 transects of 100 m. Along each transect, 10 plots with dimensions of one square meter were placed at a distance of 10 m from each other. In each plot, the type, life forms, frequency of plant species, and species density were recorded. Species diversity indices were calculated using Ecological Methodology software. The values obtained from these indicators were analyzed in SPSS 24 statistical software and using the F test. The results of the Analysis of variance (ANOVA) showed that the highest values of the species diversity indices are in the middle altitudes (ecotone) class. ANOVA of the richness, evenness, and heterogeneity indices in different altitude classes showed that the values of the richness indices were not significant, but among the indices related to the heterogeneity, the Hill index and all the evenness indices were significant. Comparing the numerical indices of our communities enables us to determine the impact of environmental stress in a single community to choose the best habitat among a similar group for conservation. A community that has high diversity and richness is important for conservation. Therefore, the authorities must prevent the destruction of the vegetation of the study area in connection with the implementation of principled and correct management by the potential of the region, but also to reduce the pressure of livestock grazing and carry out corrective and restoration operations, to turn these rangelands towards rich diversity.

Zoning of some physicochemical parameters in the sediments of Meighan wetland in Iran: response to urbanization, industrial, and agricultural activities.

Meighan wetland is located at 8 km far away from Arak city with a population of about 600,000 citizens in the center of Iran. Several agricultural activities and industries such as metal, chemical, and mineral, as well as industrial towns, exist around the desired wetland. This research was conducted to measure the sources of chemical contaminants entering the wetland through natural and artificial waterways, to explore the trend of changes in the contaminants, and to prepare the wetland contamination zone map followed by source detection of these contaminants. Sediment samples were taken during 2019-2020 from a depth of 0-30 cm from 87 points in the input waterways. The results indicated that the mean total concentrations of cadmium, nickel, lead, zinc, copper, and aluminum in sediments were estimated as 6.7, 93.4, 14.1, 276.4, 34.3, and 22,742.7 ppm, respectively. The concentrations of nitrate and phosphate in the sediments were given as 18.6 and 1.8 ppm, respectively. The mean comparison indicated that the most significant level of nickel and lead belonged to the input waterways of industrial and urban regions; the maximum cadmium content was seen in the input waterways from the agricultural lands; and the highest level of zinc and aluminum was recorded in the waterways of agricultural-industrial urban regions. There was a significant relationship between the results of classic statistics and zoning found in GIS. Overall, chemical pollutants with the origin of input wastewater from the treatment plant of wastewater and the input waterways from the industrial and urban regions have had the largest share of contamination for Meighan wetland.